SDH Synchronous Digital Hierarchy

SDH synchronous digital hierarchy.

It is a transmission method. This method is used in optical fibre transmission system called SDH system. We have already discussed the basic concepts of the transmission system. This video will give you the basic concept of SDH.

STM-1 synchronous transport module level 1.

270 column.

9 rows.

Row by Row Transmission.

Time period is 125us.

Each byte represents 64Kbps.

ITU-T recommendation G.707.

STM-1Frame Calculation.

Time period is 125us Each byte represent 64Kbps Total byte= 270*9=2430 Each byte=08 bits Total bits = 2430*8=19440 Frame Frequency=8000 Time period=1/8000=125us Data rate of one byte = 8*8000=64Kbps Data rate of frame =19440*8000=155Mb

STM-N Levels.

The basic rate of transmission 155.54 Mbps. SDH hierarchy based on multiple of 155.54Mbps.

STM-1 155.54Mbps. STM-4 622Mbps. STM-16 2.5Gbps. STM-64 10Gbps.

Higher order rate is the exact multiple of the lower order rate. It is known as a synchronous digital hierarchy.

POH Path Overhead.

Path overhead is a monitoring and alarm information field. Path overhead size varies with container size. PoH travel with the container over the path.

Virtual container = POH + Container.

VC 11, VC 12, VC 2, VC 3, VC 4.

SOH Section Overhead.

Overhead has basically the same job everywhere( Management, Control, Alarm and etc). In SDH network, Overheads are coupled with network architecture to simplify the task.

Regenerator Section Overhead (RSOH).

Pointer (AU-PTR).

It indicates the first byte of a virtual container. Its function becomes important in the case of asynchronous case.

7 Responses to "SDH Synchronous Digital Hierarchy"

Sir i really thank you.. Your videos are doubt destroyer, complex topics are explained in too much simpler way. Please make videos how to apply this knowledge on practical systems like MADM, DWDM,DXC etc. What is loop testing. How channels are divided in DWDM systems, How to make cross connections for practical circuits, How leased lines functions??